title: The roles of APOBEC3G complexes in the incorporation of APOBEC3G into HIV-1.
abstract: BACKGROUND
  The incorporation of human APOBEC3G (hA3G) into HIV is required for exerting its antiviral activity, therefore the mechanism underlying hA3G virion encapsidation has been investigated extensively. hA3G was shown to form low-molecular-mass (LMM) and high-molecular-mass (HMM) complexes. The function of different forms of hA3G in its viral incorporation remains unclear.
  
  
  RESULTS
  In this study, we investigated the subcellular distribution and lipid raft association of hA3G using subcellular fractionation, membrane floatation assay and pulse-chase radiolabeling experiments respectively, and studied the correlation between the ability of hA3G to form the different complex and its viral incorporation. Our work herein provides evidence that the majority of newly-synthesized hA3G interacts with membrane lipid raft domains to form Lipid raft-associated hA3G (RA hA3G), which serve as the precursor of mature HMM hA3G complex, while a minority of newly-synthesized hA3G remains in the cytoplasm as a soluble LMM form. The distribution of hA3G among the soluble LMM form, the RA LMM form and the mature forms of HMM is regulated by a mechanism involving the N-terminal part of the linker region and the C-terminus of hA3G. Mutagenesis studies reveal a direct correlation between the ability of hA3G to form the RA LMM complex and its viral incorporation.
  
  
  CONCLUSIONS
  Together these data suggest that the Lipid raft-associated LMM A3G complex functions as the cellular source of viral hA3G.
authors.affiliation: Institute of Medicinal Biotechnology, Chinese Academy of Medical Science, Beijing, China ; Lady Davis Institute for Medical Research and McGill AIDS Centre, Jewish General Hospital, Montreal, Quebec, Canada ; Microbiology & Immunology, McGill University, Montreal, Quebec, Canada.
authors.forename: Jing
authors.initials: J
authors.lastname: Ma
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Li
authors.forename: Jian
authors.initials: J
authors.lastname: Xu
authors.forename: Quan
authors.initials: Q
authors.lastname: Zhang
authors.forename: Zhenlong
authors.initials: Z
authors.lastname: Liu
authors.forename: Pingping
authors.initials: P
authors.lastname: Jia
authors.forename: Jinming
authors.initials: J
authors.lastname: Zhou
authors.forename: Fei
authors.initials: F
authors.lastname: Guo
authors.forename: Xuefu
authors.initials: X
authors.lastname: You
authors.forename: Liyan
authors.initials: L
authors.lastname: Yu
authors.forename: Lixun
authors.initials: L
authors.lastname: Zhao
authors.forename: Jiandong
authors.initials: J
authors.lastname: Jiang
authors.forename: Shan
authors.initials: S
authors.lastname: Cen
mesh_terms: D000071480:APOBEC-3G Deaminase; D003564:Cytidine Deaminase / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D057809:HEK293 Cells; D015497:HIV-1 / Q000378:metabolism*; D006801:Humans; D021962:Membrane Microdomains / Q000378:metabolism; D021381:Protein Transport; D054301:gag Gene Products, Human Immunodeficiency Virus / Q000378:metabolism
chemical_list: D054301:gag Gene Products, Human Immunodeficiency Virus; D000071480:APOBEC-3G Deaminase; C464924:APOBEC3G protein, human; D003564:Cytidine Deaminase